The present invention relates to a test system of a cable, and in particular, relates to an insulation and/or spark test system of a cable.
A prior cable test system (Japanese Public Notice of patent application No. 37-14502, published Sept. 19, 1962) has a differentiation circuit connected to the end of the cable to be tested, means for applying a high voltage at said end of the cable for discharging at the point where the dielectric strength is weak, a pulse transformer for transmitting a reflected pulse signal at the dielectric weak point of the cable, and means for measuring the interval of the pulse signal for the round trip to the dielectric weak point and displaying the position of the dielectric weak point.
However, the above prior system has the disadvantage that the frequency characteristics of a pulse transformer are not sufficient for transmitting the pulse signal correctly. Therefore, the pulse transformer generates an undesirable overshoot and/or back-swing waveform, which makes the result of the measurement of the distance to the dielectric weak point incorrect.